Treatments for heat rash

• In most cases, heat rash will clear up on its own in a few days if the affected area is kept cool and dry. 
• Avoid excessive heat and humidity and cool off with a fan, take a cool shower or bath and let your skin air dry, or if you have air-conditioning, use this to cool yourself. 
• Once the skin is cool and dry again, don’t use any type of oil-based product, which might block your sweat glands.
•  Calamine lotion and/or hydrocortisone cream can relieve itching and irritation.

• If your prickly heat does not go away within a few days, or if you develop an infection where the bumps have burst, you may need medication, so so seek medical advice.

Reference:webMD